[Xcb] GSoC proposal questions

Mariusz Ceier mceier at gmail.com
Wed Apr 1 23:43:05 PDT 2009

Peter Harris pisze:
> On Wed, Apr 1, 2009 at 8:15 PM, Zephaniah E. Hull wrote:
>> On Wed, Apr 01, 2009 at 05:16:34PM -0700, Barton C Massey wrote:
>>> We'll dig you up a mentor, so you really don't have to.
>>> Hopefully we can talk Peter into dealing with the hard part
>>> of it, i.e. the input side, and any of us can help mentor
>>> the XCB part.  I don't think you need to know any XCB
>>> internals; just be able to write protocol descriptions in it
>>> and build libraries atop it as far as I can tell.
>> Can the code generators actually handle some of the, unique aspects of
>> the input protocols?
>> IIRC, when I last looked at this (about a year and a half ago) there
>> were some challenges involving how XInput and friends put things on the
>> wire.
> Just off the top of my head, XInput 2 needs Generic Event support. If
> I understand correctly, XGE is going to be used for essentially all
> future extensions, so XCB is going to have to grow support for it
> sooner or later. Sooner is better, in my opinion.
So the better idea would be to implement XGE before Xi2,
do you know if it is the same for any of Xkb,Xi,Xkb2 ?
I think it is for Xkb2, a not Xkb,Xi, but I'm not sure.
It seems to be a small extension ([0,[1]), so it can be good to
implement it during community bonding period, what do you think ?

> In terms of some of the other quirks, we can either improve the code
> generator, or we can punt. xcb/util is not a bad place to put
> hand-written helper functions to deal with the most unique bits.
> There are already places where XCB punts (GetProperty/SetProperty
> doesn't have a way to specify the unit size of the data, and
> RANDR/Notify doesn't have a way to specify which of the union members
> is referenced, to pick two off the top of my head. The RANDR/Notify
> thing in particular doesn't look too dissimilar from the gaps in the
> current xinput.xml protocol description. With a little care, the
> solution for one could probably be applied to the other.)
Ok, so should I read RANDR protocol description too ( or an excerpt from
it, about Notify event ), or reading xrandr.xml will be sufficient ?

> Peter Harris

Mariusz Ceier

[0] http://lists.freedesktop.org/archives/xorg/2008-November/040871.html
[1] http://cgit.freedesktop.org/xorg/proto/xextproto/tree/geproto.txt

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